WO2011086998A1

WO2011086998A1 - Steering device

Info

Publication number: WO2011086998A1
Application number: PCT/JP2011/050296
Authority: WO
Inventors: 小野　英一; 村岸　裕治; 伸介佐藤; 大沼　豊; 仁章小野
Original assignee: 株式会社豊田中央研究所
Priority date: 2010-01-14
Filing date: 2011-01-11
Publication date: 2011-07-21
Also published as: JP2011143821A; JP5393495B2; US8515623B2; US20120173082A1

Abstract

By effecting a relation between a predetermined position of a steering wheel and the yaw angular velocity that arises upon the vehicle, a steering device aligns a direction (θ_gazeβ) of a target destination after a forward observation time that is predetermined with respect to a target course that the vehicle travels with a direction (δ_SW) of the reference position of the steering wheel, as seen from the driver's point of view. The steering device is thus capable of fostering a greater sense of unity between the driver and the vehicle, allowing the driver to steer in a manner that fits the driver's perceptions, without experiencing any sense of being out of place.

Description

Steering device

The present invention relates to a steering device, and more particularly to a steering device that realizes a relationship between a steering angle of a steering wheel and a yaw angular velocity.

Conventionally, based on experimental data, “When driving into a corner, the driver is gazing at a point that should be reached after about 1.2 seconds on the target route regardless of the vehicle speed.” A technique for setting the steering gear ratio so that the angle formed by the viewpoint is proportional to the steering wheel angle is known (Non-Patent Document 1).
Yasuo Shimizu et al., "Steering system in which gear ratio changes as a function of vehicle speed and steering angle and its effect", Japan Society for Automotive Engineers, Preprint of Scientific Lecture, No. 21-99, 1999

However, the above Non-Patent Document 1 discloses only “proportional steering gear ratio” and does not disclose a specific setting method such as proportional gain. Therefore, the technique described in Non-Patent Document 1 has a problem that if the gear ratio is too small, the actual steering angle is too large and quick with respect to the steering angle, and the driver feels uncomfortable.

The present invention has been made to solve the above problems.

In order to achieve the above object, a steering apparatus according to one aspect of the present invention includes a steering wheel direction and a direction of a target arrival point after a predetermined forward gaze time on a target course on which the vehicle travels, as viewed from the driver's viewpoint. The relationship between the steering angle of the steering wheel and the yaw angular velocity generated in the vehicle, which is predetermined so as to correspond to the direction of the reference position, is configured.

The steering device realizes a relationship between a predetermined steering angle of the steering wheel and a yaw angular velocity generated in the vehicle, thereby determining a predetermined forward gaze on a target course traveled by the vehicle from the viewpoint of the driver. The direction of the target reaching point after time is made to correspond to the direction of the reference position of the handle.

As described above, the steering device associates the direction of the target arrival point after the predetermined forward gaze time on the target course on which the vehicle travels with the direction of the reference position of the steering wheel as viewed from the driver's viewpoint. . Thereby, since the said steering apparatus can improve the unity feeling of a vehicle and a driver, it can perform the steering suitable for the driver | operator's sense without the driver feeling uncomfortable.

As described above, the steering device according to one aspect of the present invention is the direction of the target arrival point after the predetermined forward gaze time on the target course on which the vehicle travels from the viewpoint of the driver, The direction of the reference position is made to correspond. Thereby, since the steering device can improve the sense of unity between the vehicle and the driver, there is an effect that the driver does not feel uncomfortable and can perform steering in accordance with the driver's feeling.

1 is a schematic diagram showing a configuration of a vehicle steering apparatus according to a first embodiment of the present invention. It is a block diagram which shows the structure of the computer of the vehicle steering apparatus which concerns on the 1st Embodiment of this invention. It is an image figure which shows the deflection angle of the advancing direction of a vehicle, and the direction which goes to a target arrival point. It is an image figure which shows the deflection angle of the advancing direction of a vehicle, and the direction which goes to a target arrival point. It is an image figure which shows a relative depression angle. It is an image figure which shows the deflection angle of the vehicle front-back direction and the direction which goes to a target arrival point. It is an image figure which shows a mode that the head of the driver moved. It is an image figure which shows the distance of the head of a driver, and a handle | steering-wheel center. It is an image figure which shows the relationship between the steering angle of a steering wheel when a driver's head moves, a front gaze angle, and a relative depression angle. It is a graph which shows the relationship between the steering angle of a steering wheel, the relative angle of a roll angle, and a yaw angular velocity. It is a graph which shows the relationship between the steering angle of a steering wheel, and a yaw angular velocity gain. It is a flowchart which shows the content of the gear ratio control processing routine of the vehicle steering apparatus which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structure of the computer of the vehicle steering apparatus which concerns on the 2nd Embodiment of this invention. It is a graph which shows the relationship between the steering angle of a steering wheel, and a yaw angular velocity. It is the schematic which shows the structure of the vehicle steering apparatus which concerns on the 3rd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, a case where the present invention is applied to a vehicle steering apparatus that is mounted on a vehicle and controls the steering gear ratio of the vehicle will be described as an example.

As shown in FIG. 1, in the vehicle steering apparatus 10 according to the embodiment of the present invention, a steering gear ratio variable mechanism 16 is connected to a rotating shaft 14 interlocked with a steering wheel 12. An output shaft 18 protrudes from the steering gear ratio variable mechanism 16, and a pinion 20 connected to the output shaft 18 meshes with a rack shaft 22 connected to a steering wheel (not shown).

Therefore, the rotation of the steering wheel 12 is transmitted to the pinion 20 via the steering gear ratio variable mechanism 16, and the rack shaft 22 moves in the axial direction (direction of arrow W in FIG. 1). As a result, the steered wheels are steered.

The steering gear ratio variable mechanism 16 is connected to the computer 24. The steering gear ratio variable mechanism 16 has a conventionally well-known structure, and the steering gear ratio variable mechanism 16 changes the steering gear ratio of the steering gear ratio variable mechanism 16 based on a gear ratio command signal output from the computer 24. Is configured to do.

As shown in FIG. 2, the computer 24 is connected to a vehicle speed sensor 26 that detects the vehicle speed of the host vehicle and a steering angle sensor 28 that detects the steering angle of the steering wheel 12 (the steering angle of the steering wheel).

The computer 24 includes a CPU, a RAM, and a ROM that stores a program for executing a gear ratio control processing routine to be described later, and is functionally configured as follows. The computer 24 is based on map storage means 30 that stores in advance a map indicating the relationship between the steering angle of the steering wheel 12, the vehicle speed, and the yaw angular velocity gain, the vehicle speed from the vehicle speed sensor 26, and the steering angle from the steering angle sensor 28. According to the map stored in the map storage unit 30, a yaw gain calculation unit 32 that calculates a target value of the yaw angular velocity gain, and a gear ratio calculation unit 34 that calculates a steering gear ratio that realizes the calculated target value of the yaw angular velocity gain. And gear ratio control means 36 for outputting a gear ratio command signal so as to change to the calculated steering gear ratio.

Next, the principle of this embodiment will be described.

First, regarding the driver model, from the description in the specification of Japanese Patent Application No. 2009-9863, the deviation angle between the traveling direction of the vehicle and the direction of the target arrival point after a predetermined forward gaze time on the target course on which the vehicle travels. It is known that the forward gaze angle and the yaw angular velocity after a certain time have a proportional relationship without depending on the vehicle speed.

That is, the driver handles the steering wheel based on the deviation angle _θgaze (see FIGS. 3A and 3B) between the traveling direction of the vehicle (the direction of the velocity vector) and the direction of the target arrival point of the vehicle after the forward gaze time T. The predicted value r _pre of the yaw angular velocity as the vehicle motion predicted value realized by the above is calculated by the following equation (1).

However, k _r is the transfer gain from forward gaze angle theta _gaze to yaw velocity r, tau is the dead time. Here, the dead time τ is a time for matching the timing of the change of the vehicle motion and the timing of the change of the curvature of the traveling course, and is a predetermined time.

The above equation (1) is a result indicating that the driver is operating the handle based on the forward gaze angle.

As a result of theoretical analysis, and the forward fixed point time T _gaze, between the transfer gain k _r from forward gaze angle theta _gaze to yaw velocity r, the following (2) the relationship of the formula is satisfied I know that

In the present embodiment, the forward gaze time _Tgaze is set as a fixed time of 2.5 to 3.5 seconds.

Further, it is known that a relationship represented by the following expression (3) is established between the forward gaze time _Tgaze and the dead time τ.

Since the driver operates the steering wheel based on the forward gazing angle in this way, the driver passes the target reaching point after the forward gazing time with the intention of the driver. From this, by matching the direction of the forward gazing point, which is also the output of the vehicle motion, with the direction of the reference position of the handle, which is the amount of operation of the driver, as shown in FIG. In the present embodiment, attention is focused on improving operability and agility.

By the way, the forward gaze angle defined in FIGS. 3A and 3B is based on the traveling direction of the automobile. However, in order to match the relationship with the steering angle of the steering wheel, the front-rear direction of the vehicle body on which the driver is seated is determined. Need to be a standard. Therefore, in the present embodiment, as shown in the following formula (4), an angle obtained by adding a vehicle body slip angle to a front gaze angle (a vehicle front-rear direction and a predetermined front gaze time on a target course on which the vehicle travels) Let us consider matching the steering angle of the steering wheel (the relative angle between the reference position in the neutral position of the steering wheel and the current reference position of the steering wheel) with a deviation angle from the direction of the subsequent target arrival point.

Further, as shown in FIG. 4A, when the relative depression angle between the steering wheel center and the front gazing point is θ _z , the following equation (5) is obtained as a condition for the steering angle δ _sw to coincide with the direction of the gazing point. It is done.

In the above equation (5), it is considered that the handle angle is apparently cut back by the roll angle due to the roll motion. K _roll is a roll rate.

Incidentally, the forward fixed point time T _gaze, between the transfer gain k _r from forward gaze angle theta _gaze to the yaw angular velocity r, since the equation (2) of relation is established, the forward gaze angle theta _gaze, It is described by the following equation (6).

Furthermore, the vehicle body slip angle β is described by the following equation (7) from a linear model of vehicle motion.

The above expression (5) can be rewritten into the following expression (8) by the above expressions (6) and (7).

Where C _r is the rear wheel cornering power, l is the wheel base, and l _r is the center-to-rear axle distance. M is the vehicle mass, and v is the vehicle speed.

By the way, the relationship of the above equation (8) is a relationship equation under the assumption that the viewpoint position of the driver does not change. However, when the vehicle is running, it is necessary to consider that the driver posture, that is, the viewpoint position changes due to the influence of the lateral acceleration. When in proportion to the lateral acceleration of the vehicle as shown in FIG. 5A driver's head h _y moves in a direction against the lateral acceleration, the center of the handle as seen from the driver is determined by the following equation (9) θ Move outward by _d .

Here, h _x is the distance between the driver head and the center of the handle (see FIG. 5B).

Therefore, from FIG. 5C, the condition for the direction of the steering angle δ _sw when moving the driver's head (the direction of the reference position of the steering wheel) to coincide with the direction of the forward gazing point is expressed by the following equation (10). The

In the present embodiment, θ _d is formulated as shown in the following equation (11), _assuming that h _y = _{hy max} moves when the lateral acceleration is generated at 9.8 [m / s ² ].

Furthermore, the relationship between the lateral acceleration and the yaw angular velocity (conditions for preventing the slip angle from increasing) is expressed by the following equation (12).

Considering the above equations (11) and (12), a relational expression represented by the following equation (13) is derived.

Further, the relative depression angle θ _z has a relationship expressed by the following expression (14) based on the steering wheel center depression angle θ _zsw from the driver's viewpoint to the steering wheel center, the forward gaze time T _gaze and the eye point height h _eye. To do.

From the above equation (14), the above equation (13) can be described by the following equation (15).

Suppose the following formula.

From this equation, the above equation (15) can be described by the following equation (16).

In the above equation (16), as indicated by the broken line in FIG. 6, the yaw angular velocity r is a relative angle (δ _sw −φ) between the steering angle δ _sw of the steering wheel and the roll angle φ (= K _roll · r · v). It is proportional to the tangent of. The above equation (16) represents an example of the relationship between the steering angle of the steering wheel and the yaw angular velocity in the present invention.

By the way, when the steering system is controlled based on the above equation (16), the yaw angular velocity increases infinitely when the steering wheel relative to the roll angle approaches 90 deg, and the steering angle is within 90 deg. The driving operation is performed. Such a characteristic has the advantage that it is not necessary to change the handle. On the other hand, such a characteristic also has a drawback that the change of the vehicle motion with respect to the operation of steering the steering wheel may be felt sensitively and the maneuverability is impaired.

Therefore, in order to investigate changes in vehicle motion, and to investigate characteristics that impair maneuverability, tasks such as corrective steering from steady circular turning using vehicles with various yaw angular velocity gradients relative to the steering angle of the steering wheel were used. The sensory evaluation experiment which gives was performed. As a result of this sensory evaluation experiment, the upper limit of the gradient of the yaw angular velocity with respect to the steering angle of the steering wheel, that is, the steering performance is impaired when a gradient higher than this is set. The gradient of the yaw angular velocity with respect to the steering angle of the steering wheel has individual differences. It was found to be between 0.35 and 0.38 [1 / s]. This experiment was performed while changing the traveling speed, but in this experiment, no change in the upper limit value for each speed was observed. The gradient of the yaw angular velocity with respect to the steering angle of the steering wheel is a ratio (Δr / Δδ _sw ) between the variation amount Δr of the yaw angular velocity and the variation amount Δδ _sw of the steering angle of the steering wheel.

As described above, in the steering angle region where the gradient of the yaw angular velocity relative to the steering angle of the steering wheel does not satisfy the upper limit value obtained in advance based on human characteristics, the yaw angular velocity obtained based on the above equation (16) is set as the target value. . When the gradient of the yaw angular velocity with respect to the steering angle of the steering wheel calculated from the above equation (16) exceeds the upper limit value, as shown by the solid line in FIG. 6, the gradient of the yaw angular velocity with respect to the steering angle of the steering wheel is restricted to the upper limit value. It is preferable to correct the target value of the yaw angular velocity.

In this way, by setting the characteristic of the yaw angular velocity with respect to the steering angle of the steering wheel, the direction of the reference position of the steering wheel as viewed from the driver's viewpoint in the area up to the large steering angle in the foreground where changes in vehicle motion are felt sensitively And the direction of the forward gazing point can be matched. In the region of a larger steering angle, it becomes possible to steer the vehicle with a small correction steering angle without feeling sensitive to changes in vehicle motion.

In this embodiment, in order to obtain a map indicating the relationship between the yaw angular velocity gain k, which is the ratio of the yaw angular velocity and the steering angle of the steering wheel, and the steering angle δ _sw of the steering wheel, the gradient of the yaw angular velocity with respect to the steering angle of the steering wheel is In the steering angle region that is less than the upper limit value, the yaw angular velocity calculated based on the above equation (16) is converted into a yaw angular velocity gain. Further, in the steering angle region where the gradient of the yaw angular velocity with respect to the steering angle of the steering wheel exceeds the upper limit value, the yaw angular velocity corrected so as to have the gradient of the yaw angular velocity with respect to the steering angle of the steering wheel as the upper limit value is converted into a yaw angular velocity gain. As a result, a map showing the relationship between the yaw angular velocity gain k and the steering angle δ _sw of the steering wheel is obtained for each vehicle speed as shown in FIG. 7 indicates the yaw angular velocity gain derived based on the above equation (16), and the solid line indicates the upper limit of the gradient of the yaw angular velocity with respect to the steering angle of the steering wheel derived from the above equation (16). When the value exceeds, the upper limit value is restricted.

Based on the principle described above, the map storage means 30 of the vehicle steering apparatus 10 according to the present embodiment stores the steering angle and yaw angular velocity gain for each vehicle speed as shown by the solid line in FIG. A map that defines the relationship is stored.

The yaw gain calculation means 32 sets the target value of the yaw angular speed gain corresponding to the vehicle speed detected by the vehicle speed sensor 26 and the steering angle of the steering wheel detected by the steering angle sensor 28 according to the map stored in the map storage means 30. calculate.

Next, a control method for realizing a target yaw angular velocity gain calculated based on the above map will be described.

The target yaw angular velocity gain is realized by actively changing the characteristic of the steering gear ratio variable mechanism 16 provided between the steering wheel and the mechanism that steers the actual steering angle of the front wheels according to the vehicle speed. If the dynamic characteristic of the vehicle motion is ignored between the actual steering angle δ _{f of the} front wheels and the yaw angular velocity r, the relationship expressed by the following equation (17) is established.

Here, C _f is the front wheel cornering power. When the steering gear ratio between the steering angle δ _sw of the steering wheel and the actual steering angle δ _{f of the} front wheels is g _sw , the following relationship (18) is obtained.

The steering gear ratio g _sw for realizing the yaw angular velocity gain k calculated from the map shown in FIG. 6 by the above equations (17) and (18) is expressed by the following equation (19).

The gear ratio calculating means 34 calculates the steering gear ratio based on the target yaw angular velocity gain k calculated by the yaw gain calculating means 32 and the vehicle speed v detected by the vehicle speed sensor 26 according to the above equation (19). To do.

The gear ratio control means 36 outputs a gear ratio command signal to the steering gear ratio variable mechanism 16 so as to change to the calculated steering gear ratio, thereby controlling the steering gear ratio.

Next, the operation of the vehicle steering apparatus 10 according to the present embodiment will be described. A gear ratio control processing routine shown in FIG. 8 is executed in the computer 24 while the vehicle equipped with the vehicle steering device 10 is traveling.

First, in step 100, the computer 24 acquires each of the vehicle speed detected by the vehicle speed sensor 26 and the steering angle of the steering wheel detected by the steering angle sensor 28. In step 102, the computer 24 calculates the target value of the yaw angular velocity gain from the vehicle speed and the steering angle of the steering wheel obtained in step 100 according to the map stored in the map storage unit 30.

In the next step 104, the computer 24 realizes the target value of the yaw angular velocity gain from the vehicle speed acquired in step 100 and the target value of the yaw angular velocity gain calculated in step 102 according to the above equation (19). To calculate the steering gear ratio. In step 106, the computer 24 outputs a gear ratio command signal to the steering gear ratio variable mechanism 16 so as to change to the steering gear ratio calculated in step 104, thereby controlling the steering gear ratio. Return to 100.

The target value of the yaw angular velocity gain calculated repeatedly is realized by repeatedly executing the above processing.

As described above, the vehicle steering apparatus according to the first embodiment is the direction of the target arrival point after a predetermined forward gaze time on the target course on which the vehicle travels, as viewed from the driver's viewpoint, The target value of the yaw angular velocity gain is calculated and the steering gear ratio is controlled in accordance with a map showing the relationship between the steering angle of the steering wheel and the yaw angular velocity gain determined so as to match the direction of the reference position of the steering wheel. Thereby, the vehicle steering apparatus can improve the sense of unity between the vehicle and the driver, and can perform steering suitable for the driver's feeling without the driver feeling uncomfortable.

Focusing on the fact that the sense of unity with the vehicle is improved by matching the direction of the reference position of the handle with the direction of the front gazing point, so that the direction of the front gazing point visible to the driver and the direction of the reference position of the handle are matched. A yaw angular velocity gain (gain from steering angle to yaw angular velocity) was set. Such a yaw angular velocity gain is realized by a steering gear ratio such that the forward gaze angle is proportional to the steering angle tangent of the steering wheel. However, in the conventional technique, the steering gear ratio is set so that the forward gaze angle is proportional to the steering angle of the steering wheel, and the above yaw angular velocity gain is a characteristic that cannot be realized by the conventional technique.

In addition, since the forward gaze angle, which is an angle between the target arrival point after a certain time and the traveling direction, and the yaw angular velocity are proportional, the vehicle steering apparatus of the present embodiment is proportional to the tangent of the steering angle of the steering wheel. Outputs the yaw angular velocity. This means that the yaw angular velocity gain increases as the steering wheel is turned. In the conventional technique having a yaw angular velocity gain that does not depend on the steering angle of the steering wheel, the direction of the reference position of the steering wheel and the direction of the front gazing point cannot be matched in a relatively large steering region. In contrast, in the vehicle steering apparatus according to the present embodiment, the sense of unity in the large steering area can be improved as a result of the direction of the reference position of the steering wheel and the direction of the forward gazing point being coincident even in a large steering area. it can.

Further, in the vehicle steering apparatus according to the present embodiment, by limiting the gradient of the yaw angular velocity with respect to the steering angle of the steering wheel to the upper limit value obtained in advance based on human characteristics, the driver can operate in a large steering angle region. This makes it possible to steer the vehicle with a small correction steering angle without feeling sensitive to changes in vehicle motion. Therefore, the vehicle steering apparatus according to the present embodiment can improve the sense of unity between the vehicle and the driver without impairing the controllability.

Next, a vehicle steering apparatus according to the second embodiment will be described. In addition, about the part which becomes the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The second embodiment is different from the first embodiment mainly in that the target value of the yaw angular velocity is calculated and the steering gear ratio is controlled so as to realize the target value of the yaw angular velocity. Yes.

As shown in FIG. 9, the computer 224 of the vehicle steering apparatus according to the second embodiment includes a map storage unit 230 that stores in advance a map indicating the relationship between the steering angle, the vehicle speed, and the yaw angular velocity of the steering wheel 12; Based on the vehicle speed from the vehicle speed sensor 26 and the steering angle from the steering angle sensor 28, the yaw rate calculation means 232 for calculating the target value of the yaw angular speed according to the map stored in the map storage means 230, and the calculated yaw angular speed. Gear ratio calculation means 234 for calculating a steering gear ratio to be realized and gear ratio control means 36 are provided.

As a result of performing numerical calculation on the equation (16) described in the first embodiment, the relationship between the steering angle of the steering wheel and the yaw angular velocity as shown by the broken line in FIG. Obtained at every vehicle speed. Similarly to the first embodiment, by correcting the target value of the yaw angular velocity so that the gradient of the yaw angular velocity with respect to the steering angle of the steering wheel is constrained to the upper limit value, the steering wheel as shown by the solid line in FIG. A relationship between the steering angle and the yaw angular velocity is obtained for each vehicle speed.

The map storage means 230 of the vehicle steering apparatus according to the present embodiment stores a map that defines the relationship between the steering angle of the steering wheel and the yaw angular velocity as shown by the solid line in FIG. 10 for each vehicle speed. .

The yaw rate calculation means 232 calculates the yaw angular velocity corresponding to the vehicle speed detected by the vehicle speed sensor 26 and the steering angle of the steering wheel detected by the steering angle sensor 28 according to the map stored in the map storage means 230.

The gear ratio calculation unit 234 calculates the target yaw angular velocity r according to the above equation (17) based on the target yaw angular velocity r calculated by the yaw rate calculation unit 232 and the vehicle speed v detected by the vehicle speed sensor 26. The front wheel actual rudder angle δ _f that realizes is calculated. The gear ratio calculation means 234 calculates the steering gear ratio according to the above equation (18) based on the calculated actual front wheel steering angle δ _f and the steering angle δ _sw of the steering wheel detected by the steering angle sensor 28. .

Next, a gear ratio control processing routine according to the second embodiment will be described.

First, the computer 224 acquires each of the vehicle speed detected by the vehicle speed sensor 26 and the steering angle of the steering wheel detected by the steering angle sensor 28. Then, the computer 224 calculates the target value of the yaw angular velocity based on the vehicle speed and the steering angle of the steering wheel obtained in accordance with the map stored in the map storage unit 230.

Next, the computer 224 calculates the steering gear for realizing the target value of the yaw angular velocity from the vehicle speed acquired above and the target value of the yaw angular velocity calculated above according to the equations (17) and (18). Calculate the ratio. Then, the computer 224 outputs a gear ratio command signal to the steering gear ratio variable mechanism 16 so as to change to the steering gear ratio calculated above, controls the steering gear ratio, and returns to the initial processing.

The target value of the yaw angular velocity calculated repeatedly is realized by repeatedly executing the above processing.

As described above, the vehicle steering apparatus according to the second embodiment is the direction of the target arrival point after a predetermined forward gaze time on the target course on which the vehicle travels, as viewed from the driver's viewpoint, A target value of the yaw angular velocity is calculated according to a map showing the relationship between the steering angle of the steering wheel and the yaw angular velocity determined so as to match the direction of the reference position of the steering wheel, and the steering gear ratio is controlled. Thereby, the vehicle steering apparatus can improve the sense of unity between the vehicle and the driver, and can perform steering suitable for the driver's feeling without the driver feeling uncomfortable.

Next, a vehicle steering apparatus according to the third embodiment will be described. In addition, about the part which becomes the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The third embodiment is mainly different from the first embodiment in that the steering gear ratio according to the steering angle of the steering wheel is mechanically realized.

As shown in FIG. 11, in the vehicle steering apparatus 310 according to the embodiment of the third invention, the pinion 320 connected to the rotating shaft 14 interlocked with the steering wheel 12 is connected to a steering wheel (not shown). Meshed with the rack shaft 22.

Therefore, the rotation of the steering wheel 12 is transmitted to the pinion 320 via the rotation shaft 14, and the rack shaft 22 moves in the axial direction (the direction of arrow W in FIG. 1), whereby the steered wheels are steered.

The pinion gear of the pinion 320 is designed as follows.

First, from the relationship between the steering angle of the steering wheel and the yaw angular velocity gain for each vehicle speed indicated by the solid line in FIG. 7 described in the first embodiment, the steering angle of the steering wheel at a specific speed (for example, 50 to 60 km) A relationship with the yaw angular velocity gain is required.

Based on the obtained relationship between the steering angle of the steering wheel and the yaw angular velocity gain and the above equation (19), the steering gear ratio corresponding to the steering angle of the steering wheel is obtained.

The pinion gear of the pinion 320 is designed so as to realize a steering gear ratio according to the obtained steering angle of the steering wheel.

The vehicle equipped with the vehicle steering device 310 according to the present embodiment has a steering gear ratio that realizes a target value of the yaw angular velocity gain according to the steering angle of the steering wheel by the pinion gear of the pinion 320.

Thus, when the vehicle steering device 310 is traveling at a specific speed, the direction of the reference position of the steering wheel as viewed from the driver's viewpoint in the region up to a large steering angle in front of which the change in the vehicle motion is felt sensitively. The direction of the forward gazing point can be matched. In the region of a larger steering angle, the driver can steer the vehicle with a small corrected steering angle without feeling sensitive to changes in the vehicle motion.

In the above embodiment, the case where the steering gear ratio is designed according to the relationship between the steering angle of the steering wheel and the yaw angular velocity gain indicated by the map used in the first embodiment has been described as an example. It is not limited. The steering gear ratio may be designed according to the relationship between the steering angle of the steering wheel and the yaw angular velocity indicated by the map described in the second embodiment. In this case, first, based on the relationship between the steering angle of the steering wheel and the yaw angular velocity indicated by the solid line in FIG. 10 for each vehicle speed described in the second embodiment, at a specific speed (for example, 50 to 60 km). The relationship between the steering angle of the steering wheel and the yaw angular velocity is required. Based on the obtained relationship between the steering angle of the steering wheel and the yaw angular velocity and the above formulas (17) and (18), the steering gear ratio corresponding to the steering angle of the steering wheel is obtained. The pinion gear of the pinion 320 is designed so as to realize a steering gear ratio according to the obtained steering angle of the steering wheel.

In the first to third embodiments, the case where the steering of the front wheels is controlled has been described as an example. However, the present invention is not limited to this. Rear wheel steering may be controlled. In this case, the steering gear of the rear wheel that realizes the target value of the yaw angular velocity gain or the target value of the yaw angular velocity based on the formula derived using the relationship between the actual steering angle of the rear wheel and the yaw angular velocity. A ratio is calculated. Further, steering of both the front wheels and the rear wheels may be controlled. In this case, the target value of the yaw angular velocity gain or the target value of the yaw angular velocity is realized based on the formula derived using the relationship between the actual steering angle of the front wheels, the actual steering angle of the rear wheels, and the yaw angular velocity. The steering gear ratio of the front and rear wheels is calculated.

DESCRIPTION OF SYMBOLS 10,310 Vehicle steering device 12 Steering wheel 16 Steering gear

ratio variable mechanism

20, 320

Pinion

24, 224 Computer 26 Vehicle speed sensor 28

Steering angle sensor

30, 230 Map storage means 32 Yaw gain calculation means 34, 234 Gear ratio calculation means 36 Gear ratio Control means 232 Yaw rate calculation means

Claims

The steering wheel, which is determined in advance so as to correspond the direction of the target arrival point after a predetermined forward gazing time on the target course on which the vehicle travels from the viewpoint of the driver and the direction of the reference position of the steering wheel A steering device that realizes the relationship between the steering angle of the vehicle and the yaw angular velocity generated in the vehicle.
2. The steering apparatus according to claim 1, wherein a relationship between a steering angle of the steering wheel and a yaw angular velocity is realized by a steering gear ratio of the vehicle.
The steering apparatus according to claim 1, wherein the forward gaze time is 2.5 seconds to 3.5 seconds.
The steering according to claim 1, wherein a relationship between the steering angle of the steering wheel and the yaw angular velocity is determined so as to generate a yaw angular velocity proportional to a tangent of a relative angle between the steering angle of the steering wheel and a roll angle generated in the vehicle. apparatus.
The yaw angular velocity that is proportional to the tangent of the relative angle between the steering angle of the steering wheel and the roll angle generated in the vehicle is generated, and the yaw angular velocity gradient with respect to the steering angle of the steering wheel is determined in advance based on human characteristics. The steering apparatus according to claim 4, wherein a relationship between the steering angle of the steering wheel and the yaw angular velocity is defined so as to be restricted by a value.
The steering apparatus according to claim 5, wherein the upper limit value is 0.35 to 0.38 [1 / s].
A vehicle speed detector for detecting the vehicle speed of the vehicle;
A steering angle detector for detecting the steering angle of the steering wheel;
A yaw angular velocity gain is calculated based on the vehicle speed detected by the vehicle speed detector, the steering angle of the steering wheel detected by the steering angle detector, and the relationship between the steering angle of the steering wheel and the vehicle speed and the yaw angular velocity. A yaw angular velocity gain calculation unit;
A control unit for controlling a steering gear ratio so as to realize the yaw angular velocity gain calculated by the yaw angular velocity gain calculating unit;
The steering apparatus according to claim 1, comprising:
The yaw angular velocity gain calculating unit is preliminarily determined from the vehicle speed detected by the vehicle speed detecting unit, the steering angle of the steering wheel detected by the steering angle detecting unit, and the relationship between the steering angle of the steering wheel and the vehicle speed and the yaw angular velocity. The steering apparatus according to claim 7, wherein the yaw angular velocity gain is calculated based on the relationship between the steering angle and the yaw angular velocity gain that are obtained.
A vehicle speed detector for detecting the vehicle speed of the vehicle;
A steering angle detector for detecting the steering angle of the steering wheel;
A target yaw angular velocity is calculated based on the vehicle speed detected by the vehicle speed detector, the steering angle of the steering wheel detected by the steering angle detector, and the relationship between the steering angle of the steering wheel and the vehicle speed and the yaw angular velocity. A yaw angular velocity calculation unit;
A control unit for controlling the steering gear ratio so as to realize the target yaw angular velocity calculated by the yaw angular velocity calculating unit;
The steering apparatus according to claim 1, comprising: